#define _CRT_SECURE_NO_WARNINGS 1
#include<bits/stdc++.h>
using namespace std;
int main()
{
	double s, a, b;
	cin >> s >> a >> b;
	printf("%.6f\n", s * (b + a) / b / (b + 3 * a) + 2 * s / (b + 3 * a));
	return 0;
}